The present invention relates generally to lightweight display structures or frames and, more particularly, to a connecting device or coupler for connecting together the structural members used to form a frame.
This invention is related to the invention described in my copending U.S application, Ser. No. 353,901, filed Feb. 21, 1989 now U.S. Pat. No. 4,934,858. Display frames, generally known as "space frames" are constructed using lightweight interchangeable modular framing elements and connectors. Such frames and connecting devices are known in the prior art.
One example of a frame and connecting device is disclosed in AU 4,444,424 (to Whisson), directed to a demountable frame including a joining means. The joining means comprises a first and second spigot means including locating surfaces which project into a first frame member and engage against the walls of a frame member and the opposite face of the other spigot. Similarly, U.S. Pat. No. 2,926,941 (to Thompson) is directed to another device for connecting frame members together. The Thompson device includes a connector formed of two mating half portions that have hollow projections; the projections have tapered surface areas and a shoulder at the end of the taper. U.S. Pat. Nos. 3,356,395, 3,362,738, and 3,888,440 disclose fastening devices which include features to positively lock the structural members into place or contact.
The prior art also includes a series of Unistrut Corporation patents (U.S. Pat. Nos. 3,270,478, 3,443,348, 3,914,063 and 3,927,499, among others). These patents are directed to or include disclosure of connecting fixtures for use with "space frame" structures.
The above-noted prior art does represent significant advances in the art of assembling modular, display or "space frame" structures. However, there are problems which have remained unaddressed.
The present invention provides a space frame having a smooth, finished looking surface with no protrusions or fastening devices extending from the surface or joints of the frame members while yet permitting a positive or active locking mechanism to insure that the frame, after being assembled, is stable and supportive of loads placed on it. A related advantage of the present invention is that it overcomes the problem that hardware traditionally associated with assembling display frames can interfere with display panels, shelves or the like which may be attached to the frame following its assembly.
The invention also provides a self-aligning connecting device which enables structural members to be correctly positioned prior to being locked into place, thereby facilitating proper alignment of the members comprising the frame structure; it also meets the need to provide a coupler or connecting device which will connect structural members so that the support structure frame may be assembled or disassembled without using any special tools or other tools such as screwdrivers, pliers or the like and the need to provide a coupler which does not require the use of conventional fasteners such as nuts, bolts, screws or pin/aperture connections.